After losing Ryan Mathews to a broken clavicle, the Chargers have no plans to add depth at running back.

The way they see it, they already have.

Mathews suffered the injury during his first carry of the first quarter of the Chargers' first preseason game Thursday night. He is expected to miss four to six weeks and is considered unlikely to play in the season opener against the Raiders.

Chargers General Manager A.J. Smith said Friday the team will stand pat with the backup options in place.

“We made a concerted effort to add quality, proven veteran players at many positions," Smith said. "There’s a reason why (Le'Ron) McClain, (Ronnie) Brown and (Jackie) Battle were added. Curtis Brinkley is a talented kid, and that’s why he’s been in our program for three years.

"It’s next man up time. We are about to see how well we did with our offseason running back choices. Coach (Norv) Turner will sort it all out in the next three games.”

Turner has been highly complimentary of Brown during training camp.

On Friday, he called him a "complete back."

Brown could see the bulk of touches as the Chargers mix in McClain in certain situations, including short yardage.

But, as Smith alluded, all that will be ironed out over the course of the preseason.

"I like our backs," Turner said. "I like the guys we have here, and I'm excited about them and what they've been doing. We'll just get ready to go with the guys we have until Ryan is ready. ... Ryan will come back healthy. He's on his way to having a great season, and I don't think this will detour that."

The Chargers identified depth as a contributing factor to their current two-year playoff drought.

So, they addressed it.

Smith was active in free agency, picking from what he labeled the deepest group of free agency options in NFL history. The Chargers entered training camp with 20 veterans signed since March, 16 of which were not on the roster last year.

At running back, along with signing Brown, Battle and versatile fullback McClain, the team took Edwin Baker in the seventh round and signed undrafted rookie Michael Hayes, adding them all to Mathews, Brinkley and fullback Jacob Hester.

If Mathews indeed misses the start of the season, his absence may mark the first true test of the Chargers' depth.

“Some air came out of the balloon last night, for sure," Smith said. "But it’s full today. It’s disappointing for us to have to start the season without Ryan. But disappointment lurks around every corner in the NFL. You don’t ever dwell on it. You deal with it right now.”

–Turner said he is excited about how much more active and athletic the defense's front looked in the first preseason game. “If you were paying attention to that,” he said, “I think it was pretty obvious that that's going to be a big upgrade for us.”

Nuts 'n' Bolts

• Turner said he was excited about how much more active and athletic the defensive front looked in the first preseason game. “If you were paying attention to that,” Turner said, “I think it was pretty obvious that that's going to be a big upgrade for us.”

• The Chargers have two remaining practices open to the public, today and Sunday from 3:45 to 6 p.m. at Chargers Park.

• No injury update was provided on safety Darrell Stuckey, who suffered a stinger Thursday. His availability for today's practice is not known.